Expansion of aromatic heterocyclic polymers in salt solution
| Autor: | Thaddeus E. Helminiak, Thomas R. Hanley, Charles L. Benner |
|---|---|
| Rok vydání: | 1978 |
| Předmět: |
inorganic chemicals
chemistry.chemical_classification Polymers and Plastics food and beverages chemistry.chemical_element General Chemistry Polymer Conductivity Chloride Surfaces Coatings and Films chemistry.chemical_compound Viscosity chemistry Polymer chemistry Materials Chemistry medicine Lithium chloride Molecule Lithium Solubility medicine.drug |
| Zdroj: | Journal of Applied Polymer Science. 22:2965-2978 |
| ISSN: | 1097-4628 0021-8995 |
| Popis: | The addition of lithium chloride to solutions of poly(5,5′-bibenzimidazole-2,2′-diyl-1,3-phenylene) (PBI) and N,N-dimethylacetamide (DMAC) resulted in the elongation of the PBI molecule in solution. This elongation is due to the association of lithium and/or chloride ions in the region of the nitrogen atoms on the polymer chain. The presence of these ions expands the polymer chain by means of electrostatic repulsion. This effect was reflected in the results of the conductivity and viscosity studies. In general, LiCl can be used for both increased solubility and increased viscosity for this system. A ratio of 0.125 g LiCl/gram PBI was determined to be the optimum amount of LiCl to be added. This amount corresponds to mole of LiCl for every mole of PBI repeat unit. The PBI molecule was determined to have entanglements in concentrated solution at every 27 or 28 molecules along the polymer chain. This length between the entanglements is very low in comparison to other polymers indicating a strongly matrixed system. The chain length between entanglements was approximately the same for both PBI-DMAC and PBI-LiCl solutions. |
| Databáze: | OpenAIRE |
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